Presently, biologically compatible air-based pressure monitoring catheters are used in a number of medical applications to monitor pressure at various locations within a mammalian body. For example, air-based pressure monitoring catheters may be inserted into the skull of a patient thereby permitting the external monitoring of intra-cranial pressure.
Currently, a number of air-based pressure monitoring catheters have been developed. Generally, these air-based pressure monitoring catheters comprise a catheter having an air lumen formed therein which communicates with a bladder positioned at or near its distal end. In addition, the catheter includes a connector located at or near its proximal end which may be connected to an external pressure transducer. During use, the volume of the bladder attached to the catheter changes as pressure varies in accordance with Boyle's Law (P1V1=P2V2). As a result, the pressure of the gas within the catheter becomes equal to that of the environment surrounding the bladder. The media surrounding the bladder must be capable of movement to accommodate the variations in bladder volume as pressure changes. As such, pressure monitoring within a flowable liquid media has not proven difficult as the media is capable of accommodating the variations in bladder volume. However, one shortcoming of currently available air-based pressure monitoring catheters becomes evident when used to measure the pressure within an enclosed space, such as when used to monitor intra-cranial pressure.
When used to monitor intra-cranial pressure the bladder may become over inflated as a result of the movement of the media. As a result, the bladder may exert excessive force on the surrounding brain tissue as the brain tissue continues to move in response to changes in the intra-cranial pressure. The brain tissue, positioned within the skull, has a limited ability to move in response to the changes in bladder volume. As a result, the continued exertion of excessive force by the bladder on the surrounding brain tissue could result in a stroke, brain damage, or death.
Similarly, the use of air-based pressure monitoring catheters in negatively pressurized environments has proven problematic. Typically, a deflated bladder will immediately inflate to a pressure equal to environment surrounding the bladder the when introduced into a negatively pressurized environment. During use, the bladder may be capped to isolate the bladder from the external environment thereby permitting the accurate monitoring of pressure within the body. Often excessive air may be unintentionally injected into the bladder while connecting the pressure monitoring device to a pressure transducer. As a result, the over inflated bladder may exert an excessive and detrimental force on the surrounding tissue.
Thus, in light of the foregoing, there is a ongoing need for a pressure monitoring connector capable of connecting a gas column pressure monitor to a pressure transducer.